collection.each(lambda x: ... ... ) Or if the language doesn't require () to call a method, and uses `do` instead of `lambda`: collection.

collection.each(lambda x: ... ... ) Or if the language doesn't require () to call a method, and uses `do` instead of `lambda`: collection.each do x: ... ... If it's not the first argument: map(lambda x: ... ... , collection) Yes this is ugly, but using a multi line anonymous function in the middle of an argument list will always be ugly.